What are the Single Flange level transmitters in Industrial Applications?

1. The Single Flange Level Transmitter is a field transmitter installed directly on the pipeline or vessel. 

The single flange level transmitter can also be used for precise level and density measurement of all types of vessels and is divided into two kinds: flush and plug-in flange, due to direct contact between the isolation diaphragm and the liquid medium. Therefore, leading the positive pressure side with a pressure guide tube is unnecessary, suitable for high temperature, high viscosity, easy crystallization, manageable precipitation, strong corrosion, and other media measurement.

At present, there are many ways to measure the liquid level in closed containers, and standard measuring instruments include magnetic flap level meter, double flange differential pressure transmitter, single flange differential pressure transmitter, differential pressure transmitter, radar level meter, and so on.

The magnetic flap level meter is easy to lose magnetism in certain environments leading to level meter failure; the radar level meter has high accuracy, but the investment is larger, while in the early stage of operation due to more sources of signal interference, which has a greater impact on the measurement and requires frequent removal of false signals; the differential pressure transmitter has a lower cost, high measurement accuracy and fewer sources of interference, so the differential pressure principle is more commonly used to measure the level in closed vessels.

2. What is Single flange level transmitter?

The single flange transmitter is divided into two types of insert and flat flange. The transmitter measurement principle and installation method are the same, but the different process conditions on the transmitter measurement data have a huge impact. Taking the steam condensate flash barrel in the salt industry as an example (see Figure 1), A is the steam condensate inlet, B is the flash steam outlet, C is the installation position of the mono flange transmitter, D is the steam condensate drainage pipe, and point E is the negative pressure side of the mono flange transmitter taking the pressure point.

When selecting a suitable instrument, We tend to ignore the impact of water flow on the pressure. If the A point and the barrel tangent vertical, the water in the barrel will not form a vortex, but the water column falling from the A point will affect the measurement of the pressure at the C point, resulting in uni flange transmitter positive pressure side measurement data instability; if the A point and the barrel tangent is not vertical, the water in the barrel will form a vortex, regardless of the location of the C point in what will cause the single flange transmitter positive pressure side measurement data distortion. Considering the flashing efficiency of steam condensate, in general, point A and the barrel tangent direction parallel to the inlet method. Such a barrel will inevitably form a vortex. Therefore, the selection of the transmitter is crucial.

3. What is Plug-in single flange transmitter with flat flange transmitter?

My company at the beginning of the selection of the impact of water flow on the pressure, the choice of inserted mono flange transmitter in use after the liquid level is often low, due to the inaccuracy of the level meter, automatic adjustment of the story of the regulating valve can not be used commonly, only by the operator in the field to observe the glass tube level meter for the barrel level adjustment, increase the amount of T work not to say that the level control is not reasonable, flash inefficiency, to This increases the amount of work, but also the level control is not reasonable. The flashing efficiency is low, causing a significant impact on production.

At first, we suspected that the problem was with the mono flange transmitter, and after testing, we found that everything was fine with the transmitter in the laboratory. Later, after careful observation of the site process piping. Although we found that the transmitter measurement value fluctuates, we confirmed that the water flow caused the data to lose truthfulness after analysis.

As shown below in the picture, Point A is the condensate’s inlet pipe, and point B is the installation position of the insertion type mono flange transmitter. The inlet pipe is along the tangential direction of the barrel into the water, the barrel to form a vortex, inserted into the positive pressure diaphragm of the mono flange transmitter in the vortex water flow. The impact of the water flow caused the transmitter positive pressure measurement point pressure instability, measurement data distortion. As the steam condensate bucket belongs to the pressure vessel, can not open at will to transform, so the solution to the problem can only be to replace the transmitter.

As shown above the picture, Points A and B are the same as Figure 2, C for the tank wall to take the pressure point between a piece of stagnant water. This piece of stagnant water is isolated from the tank vortex and flat flange level transmitter positive pressure diaphragm. The transmitter in point B measured the pressure is not affected by the vortex water pressure in the barrel. After determining a good solution, we will be inserted into the mono flange level transmitter back to the factory converted into a flat flange level transmitter. The instrument runs smoothly through the transformation, clear bottom to eliminate the condensate balance barrel level data distortion.

Whether it is an insertion type mono flange level transmitter or a flat flange level transmitter ultimately belongs to the differential pressure transmitter, the principle of measuring the level is through the formula P = pgh to calculate the pressure of the medium at full liquid level, then the range of the transmitter is negatively relocated after the height of the liquid level in the container is calculated through the differential pressure. Therefore, the level can only be correct if the pressure measurement is accurate. The advantage of the plug-in type mono flange level transmitter is that it is not easy to block the tube in viscous, large particle media, but it is still somewhat weak in dealing with fluid impact in a more severe environment. To sum up, in the instrument selection process, we should consider the instrument’s price, brand, material, and other issues and focus on whether the device is located in the region of the working conditions can make it stable and reliable operation is also crucial.