What are the best modification options for the pump flow in the liquefied gas automatic loading system?
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Our liquefied gas loading pump is a magnetic pump without a minimum flow rate requirement, and the loading system uses automatic filling; once filling is complete, the filling valve closes automatically. At that point, the liquefied gas pump continues to operate. If no one is monitoring the pump on site, it can suffer significant damage. I would like to ask what the most reasonable approach is for the pump’s operation process, so as to achieve automatic control.
Our company uses manual loading for liquefied gas loading, and centrifugal pumps work very well; the compressors we used before weren’t effective, so we might consider replacing them with pumps
The simplest solution is to add a return line.
Pumps should generally be equipped with safety check valves to prevent overpressure
Quantitative loading is used; the valve closes automatically and the pump stops once it is full.
The scheme of automatic valve closing and pump shutdown is feasible for centrifugal pumps, but not suitable for magnetic drive pumps!
Add bypass lines at the pump inlet and outlet for backflow.
I have a good solution for you: use an inverter. That’s how I design my systems, and homeowners find them to be very effective. Domestic frequency converters are also cheap
Is it possible to use a interlocking mechanism between the valve and the pump, so that the pump shuts down simultaneously when the valve is closed?
Let’s strive to make this response a classic one, O(∩_∩)O~ There are several ways to address the original poster’s question: 1. Set up a return line, so that when filling stops but the pump continues to run, the medium can return through this return line. 2. Install a frequency converter on the pump. 3. Those in the process control field are requested to consider the interlock between pump operation and the loading crane pipe. 4. Install a quantitative loading system. Comparing the above points, I personally think it’s best not to use the first one, as it seems like a waste. The latter methods are all good options, hehe; I hope my answer is useful to you!
Hehe, regarding the loading of liquefied gas in fixed quantities, it’s different from other liquids: there is a gas phase that needs to be returned, so flow meters cannot be used; instead, scales are required. Due to the limitations on the flow rate at which liquefied gas can be loaded, many hoses are needed, and using scales results in high costs, making it an unattractive option. What I do is to close the valve in a controlled manner using a flow meter, and then weigh the material on a scale, using that value as a basis for trade calculations. The sequence is to close the valve and stop the pump. Even for quantitative loading and the chain industry, a return pipe is required. Provide a return pipe. This is the usual practice. Many people do this. The reason is that the valve used for loading is an electro-hydraulic valve or a control valve, which initially controls the flow rate at a low level, then increases it to a faster pace, and finally slows it down again. We know that pumps have a flow and head curve; when the flow rate is low and increases, overpressure may occur. Additionally, the effect of water hammer must be considered, so it is advisable to use a return pipe. But a better solution is to use an inverter, which can address the problems of water hammer and overpressure; it also saves energy compared to using a backflow mechanism. Explanation: Quantitative loading, interlocking functions, and backflow are all necessary (my design does not include a backflow mechanism; instead, an inverter is used). Last edited by Storage and Transportation Engineer on 2009-3-5 at 12:20
All of the above methods can be used; flow meters can be installed in both gas and liquid phases, so what storage and transportation engineers say is also one-sided. Hehe, it’s just that the mass flow meter is a bit expensive.