Measuring principle and structure of float level gauge

What is the measurement principle of the float level gauge? What are the classifications of float level gauges? Instruments for liquid level detection based on buoyancy are collectively referred to as buoyancy type liquid level detection instruments. Buoyancy type liquid level instruments are divided into constant buoyancy and variable buoyancy type liquid level instruments according to whether the buoyancy of the sensor changes with the liquid level. The buoyancy of the constant buoyancy type liquid level instrument does not change with the height of the liquid during operation, that is, the sensor always floats above the liquid surface, and the height of the sensor is the height of the liquid. There are many types of such liquid level detection instruments, such as floating Disk, float, float and other level gauges. The buoyancy of the variable buoyancy liquid level instrument during operation will change with the height of the liquid. The sensor cannot float in the liquid, and the height of the sensor cannot represent the liquid level of the liquid. Other conversion methods are required to know the liquid level. Height, the most widely used liquid level detection instrument is the displacer level gauge. The structure and measurement principle of the float level gauge The structure and measurement principle of the float level gauge The sensor of the float level gauge - the float will not float with the change of the liquid level during the whole detection. The reason for this phenomenon is that Because the float of the float level gauge sinks much more than the float and the floating disc, the buoyancy of the float is not enough to overcome its own gravity and float. Even if the liquid level is full and the float is fully immersed in the liquid, the buoyancy of the float cannot overcome its own gravity, so the float level gauge is also called a sinking level gauge. Measuring principle When the measured liquid has no liquid level, the buoy is not subject to buoyancy, the connecting wire connected to the top of the buoy is in a tight state, and the torsion bar is affected by the gravity of the buoy to generate a fixed torsion force. At this time, the buoy level gauge should output 4. mA current, that is, the zero point of the float level meter. When the liquid level of the liquid to be measured rises, the liquid enters the measuring cylinder, and the volume of the liquid discharged by the float rod increases with the rise of the liquid level. According to Archimedes' law, the buoyant force on an object is equal to the volumetric weight of the liquid displaced by the object. Since the buoy rod is a metal tube with a small size and weight, the weight of the liquid discharged by the buoy is far less than the weight of the buoy itself, so the connecting parts on the upper part of the buoy are still in a tight state, and the torsion bar bears the gravity of the buoy minus the discharge from the buoy. The weight of the liquid (buoyancy of the buoyancy) produces a changing torsion, at which point the buoyancy level gauge outputs a changing current greater than 4 mA. When the liquid level of the liquid to be measured reaches the highest level, the buoy is completely immersed in the liquid to be measured, and the volume weight of the liquid discharged from the buoy is a fixed value. The weight of the liquid discharged by the float, the torsion bar bears a fixed torsion force at this time, and the current output by the float level gauge is 20 mA, which is the fullness of the float level gauge. According to Archimedes' law, the tensile force on the upper connecting wire of the float during the whole liquid level measurement process is F= mg-ρVg=G -πd2/4ρgH In the formula, G is the weight of the float, d is the outer diameter of the float, and ρ is the To measure the density of the liquid, H is the height of the liquid to be measured. The above formula is converted into: H=4(G-F)/πd2ρ=K(G-F)/ρ In the formula, K is a fixed constant 4/πd2. It can be seen from the formula that the tensile force F on the steel wire is constant at the liquid density ρ In the case of , it is inversely proportional to the height H of the measured liquid corresponding to a single value. As long as the tension F of the upper wire of the buoy is detected, the height of the liquid to be measured can be obtained. The structure of the float level gauge 1. Classification of the float level gauge The float level gauge is also divided into two types: inner float and outer float according to the different positions of the float. The so-called internal and external division refers to the place where the float is installed. The inner buoy is in the container for measuring the liquid, and the outer buoy is called the outer buoy outside the container of the liquid to be measured. The inner buoy liquid level gauge itself does not have a measuring cylinder, and the buoy is directly installed in the container filled with liquid. Inner float level gauges are mounted vertically on top of these vessels via a top flange. The external buoy liquid level gauge itself has a measuring cylinder. The measuring cylinder is connected up and down with the side of the container of the liquid to be measured through the interface flange to form a communication device with equal liquid level. The buoy is suspended in the center of the measuring cylinder through the top torsion bar and connecting wire. . Second, the structure of the float level gauge The float level gauge is mainly composed of the following parts: the float, the connecting piece (steel wire, fixed card), the torsion bar, the torsion sensor transmitter and the measuring cylinder (outer float) and other surface bodies appendix. The buoy is a metal tube with a thick wall welded at both ends, and an interface ring is left at one end as the upper end of the buoy. The connecting wire is a stainless steel strip with reduced toughness. One end is connected and fixed on the pull ring of the buoy, and the other end is fixed on the fixing card of the torsion bar. The torsion bar is a mechanical torsion arm that pulls the tension on the connecting wire generated by the interaction of the buoy's gravity and the liquid buoyancy.Converted to axis displacement in rotation about the axis. The torque sensor transmitter detects and converts the shaft displacement on the torsion bar arm, and then compares it with the internal program parameters of the transmitter to calculate the liquid level height at this time, display and output the standard current signal for remote transmission. Realize liquid level detection.
KAIDI saves time and increases productivity because it's one of the most complete sources of business and contact information.
With continuous operational improvements, expanding capacity and a strong competitive position for serving strategic domestic markets, Guangdong Kaidi Energy Technology Co., Ltd. are positioned for long-term growth that will benefit our customers and investors.
Guangdong Kaidi Energy Technology Co., Ltd.’s mission is to provide you with an outstanding member/Customer benefit that helps you meet your organization’s objectives.