How to achieve uniform feeding under vacuum conditions?
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Dear students, there is a system that needs to achieve a uniform feeding rate of 5–15 kg/hour, with the material being a flowable paste The system is under high vacuum conditions. The equipment manufacturer originally designed it with a backpressure valve and a diaphragm metering pump, but in actual use it was found that uniform feeding could not be achieved at all; the material was fed in an intermittent manner! It is recommended to switch to a peristaltic pump or a mass flow meter combined with an inverter-driven pump! Peristaltic pumps are inexpensive and easy to implement; I plan to give them a try. Dear sea friends, thank you in advance for any good suggestions! ! !
Due to the working principle of diaphragm pumps themselves, their performance features peaks and troughs similar to those of a pulse, with relatively poor uniformity; back pressure can help reduce the difference between these peaks and troughs. Screw pumps and peristaltic pumps perform well, while piston pumps and diaphragm pumps perform less well
You can try a gear pump or a screw pump~~
Diaphragm pumps can also achieve this; one motor with multiple pump heads enables steady material supply!
Mass flow meters are not suitable for such applications. On one hand, the flow velocity is extremely low, and mass flow meters cannot provide accurate measurements at such low velocities; they become practically unusable when the ratio exceeds 100:1. Even within this range, ideal installation conditions are required to ensure long-term reliability； On the other hand, the fluctuations in your flow rate will be relatively large, which requires a mass flow meter with excellent real-time performance; in other words, it needs to have a fast update rate. As a result, the stability of the entire system (which is a second-order system with feedback) will deteriorate. This is a contradiction, and it’s not possible to achieve your goals unless PID control is added as an additional measure.