Bubbling (blowing) level gauge suppliers

This type of level gauge can be designed by oneself; there’s no need to purchase one from a manufacturer. The principle of this level gauge is very simple; those with basic knowledge of instruments should be able to assemble one on their own without any problems.

As the friend on the 2nd floor said, this can be made by oneself; all that’s needed is to purchase a differential pressure transmitter with stable performance. The following information may be helpful for the original poster in using this instrument. The blowing method is commonly used for level measurement in process media that are highly viscous, highly corrosive, prone to solidification or crystallization, or contain suspended particles. Depending on the medium and the constraints imposed by the processing conditions, various types of purge gases are used: non-toxic and harmless gases such as air and nitrogen, as well as highly toxic gases like carbon monoxide. To successfully use the blowing method for measuring the level of special media, in addition to designing a proper blowing scheme and selecting appropriate blowing parameters, another crucial factor is mastering the techniques for installing the gauge on-site. This article takes the use of the CO purge method to measure the liquid level in a certain reactor as an example to explain the operating procedures for installing a purge-type level gauge. http://yunrun.com.cn/upload/201802/07/201802072245506327.jpg Figure 1: Operation steps of the purge-type level gauge. yunrun.com.cn/tech/1072.html As shown in Figure 1, the purge-type level gauge consists of two rotameters M1 and M2 equipped with controllers, four shut-off valves V1-V4, and a differential pressure transmitter T (accompanied by a three-valve assembly V5-V7); it uses CO gas that has been filtered and pressure-stabilized for purging purposes. When putting the level gauge into use, first shut off valves V1-V4 on the purge line, close the control needle valves C1 and C2 of the flow controller on the rotameter, as well as the gas and liquid inlet valves V8 and V9 on the equipment. Then, slowly open the inlet valve V1 on the gas purge line and the regulating needle valve C1 of the flow controller. Use the C0 detector to check for leaks in the pipeline section from the inlet valve V1 to the outlet valve V2 on the side of the flow meter M1 (for non-toxic and harmless gases, soapy water can be used to detect leaks). After confirming there is no leakage, open the outlet valve V2 and turn the adjusting needle valve C1 so that the float of the flow meter is at the 50%-80% position. Pause for a moment and observe whether the float of the flow meter drops. If there is a drop, the opening of needle valve C1 can be increased further to boost the flow rate and allow the float to rise back to the aforementioned position. Repeat this process multiple times until C1 reaches the fully open position and the measurement value returns to zero; this indicates that there is no leakage in this gas purge line between the inlet valve V1 and the root valve V8. Conversely, if after a certain period of time the flow rate stops decreasing due to adjustments to the opening degree of C1 (possibly before C1 has reached its full open position), and remains stable at a certain value, it indicates that there is a leak somewhere along this pipeline between V2 and V8; such a leak must be located and fixed. This is the most crucial step in determining whether the puff method measurement is successful. It should be noted that the above inspection process is related to the pipeline length. Under normal conditions with no leaks, the longer the pipeline, the longer it takes for the flow to stop; patience is required when observing this phenomenon. But in any case, it is necessary to see the float stop at the “zero” position (i.e., zero flow) in order to truly confirm the situation ； During inspection, the differential pressure transmitter unit should be connected and tested together. To prevent one-sided pressure on the differential pressure transmitter, when performing this check, the balance valve V6 can be opened, and the pressure tap valves V5 or V7 on either side can be closed. Using the same method as described above, inspect the gas injection pipeline on the liquid phase side. After the inspection is complete, close valves V1-V4 on the air supply pipelines on both sides as well as needle valves C1 and C2 on the flow controllers. Set the three-valve assembly of the differential pressure transmitter to the position where the balance valve is open and the high and low pressure valves are closed, then proceed with the next steps. Disconnect the connection at the end of the purge line connected to the vapor-phase root valve V8, open the purge gas inlet and outlet valves V1 and V2 on that side, adjust C1 to maintain a constant flow rate (trying to keep the float around 80% of the scale), and purge the line in order to remove any residual fluid that may be present in it. During purging, to prevent CO poisoning, it is necessary to pay attention to the wind direction and to ensure that one’s own position as well as those of others are safe; one must not leave the area at any point during this process. If necessary, a collector can be installed at the disconnection point at the end of the pipeline to prevent the leakage of CO gas and residual medium. The purging time is determined empirically based on the length of the pipeline, and is generally around 0.5–1 minute. Once it is believed that the purging is complete, close the inlet and outlet valves V1 and V2, and turn C1 to the fully closed position. Follow the same steps to purge and blow out the other side (the liquid phase). Unless it is the initial startup or there is a definite certainty that no residual liquid remains in the pipeline, it is advisable to perform this procedure for each time the gauge is read during maintenance. Thereafter, reconnect the gas and liquid phase ends that were separated earlier, open the air inlet and outlet valves on the corresponding sides, and \"pressurize\" the pipelines on both sides using a method similar to the one mentioned earlier for checking for leaks. To speed up the “pressurization” process, it is often possible to turn the control needle valves (C1 and C2) on the flow meter directly to the fully open position. When the float position drops to “zero”, it is considered that the “pressurization” is complete. However, at this point it might happen that the flow meter float does not return to \"zero\"; this is certainly due to a lack of sealing at the connection point when restoring it. It is necessary to reconnect carefully so that the float eventually returns to \"zero\", thereby ensuring complete \"pressurization\". Finally, slowly open the root valves V8 and V9 for the gas and liquid phases, and stabilize the flow rate of the gas by adjusting the knobs C1 and C2 on the flow controller (usually by positioning the float in the middle of the flow meter scale). Open the high and low valves V5 and V6 of the three-valve assembly, close the balance valve V7, and activate the differential pressure transmitter. At this point, the air-actuated level gauge can operate properly. In short, provided that the design is sound and the installation follows proper standards, and as long as the meter is properly installed and put into use in light of the actual conditions on site, then this simple and effective measurement technique of using air-blown level gauges to measure the level of special fluids can certainly achieve the desired measurement results and meet the needs of process control.