Regarding liquid metering
Thread Content
I would like to ask everyone: what methods are used in chemical production to accurately measure liquid materials? How to achieve an accurate addition amount?
1. The pressurized feed is metered using a rotameter! 2. The weighing device uses a metering control system (electronic scale) to measure the feed amount ； 3. Use a metering pump to deliver the liquid; the metering pump is used for measurement.
1 Metering tank 2 Metering pump 3 Flow meter
What the classmate upstairs said is correct; these are the common methods used: 1. Metering tank – used for intermittent, small-batch metering, which ensures that the amount of material added each time is roughly the same. However, the operating pressure is usually not very high, and it’s necessary to ensure that the metering tank can be pressurized to a level higher than that of the downstream equipment, so as to force the material into it. Suitable for process media with good fluidity. 2 Metering pump – commonly used for continuous feeding, it serves both to meter the flow and to increase pressure; it can usually be used in combination with a flow meter to ensure accurate dosing. A metering pump can generally adjust the feed flow by adjusting its stroke or speed. 3 Flow meter – typically used for continuous feeding; generally, the pressure upstream is higher than that downstream, and it is often used in combination with a control valve to regulate the feed rate. It should be noted that there are many types of flow meters, and the choice must be made based on the properties of the process medium. Common types include rotameters, venturi differential pressure flowmeters, calorimetric mass flowmeters, vortex flowmeters, and mass flowmeters, among others. 4. Weighing and measurement – generally used for measuring solids and liquids; the entire device is weighed as a whole, and the amount of material added to the system is calculated based on the weight difference. It is usually used in combination with a downstream shut-off valve
Metering pumps are widely used, with the choice mainly depending on the required precision.
If the raw material comes in in barrels, and it needs to be sent to a metering tank, what should be done? High precision is required, and there must be no residues at the bottom of the barrel
What are the properties of the material inside the barrel? Can it be exposed to air? Is it harmful? Can the barrel itself withstand pressure? If the material in the bucket is harmless and can come into contact with air, the best approach is to use a pneumatic pump to transfer it into the metering tank, and then pour the remaining liquid into the tank using a funnel. If the substance in the bucket cannot come into contact with air and is harmful, use a pneumatic pump to feed it in, and finally tilt the bucket so that as much of the material as possible can be transferred out. If the tank can withstand pressure, then it’s simple: connect nitrogen, insert the low-pressure tube, and push all the material into the metering tank
Weigh it with a balance and add it in intervals.
It is best to use a mass flow meter! This is more standard! !
Flow meter (it is said that mass flow meters are very accurate), automatic valve, DCS system, automatic control. The valve automatically closes once a certain amount has been set.
Adding a flow meter behind the metering pump gives the most accurate results, haha