Regarding the selection of flow switches
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The unit I work in is equipped with a flow switch designed to measure the flow rate in 1-inch pipes; it triggers an interlock to shut down the discharge pump when the flow rate is low. The medium in question is quite viscous and has a high solid content, resembling a gel. Initially, a thermal mass flow switch was used, but the sensor was often covered by the medium, which prevented alarms from being triggered when there was no flow, resulting in damage to the pump. The problem with the tuning fork switch remained unchanged; after investigation, it was found that the tuning fork was covered. Please ask an expert to recommend a suitable traffic switch for me. (I wouldn’t recommend using a flow switch with a radiation source.) Thank you!
This post was last edited by “Hasty Passerby” on October 25, 2017, at 22:04. It is recommended to consult regarding target-type flow switches; if mechanical ones don’t work, there are electromagnetic types mentioned in the documentation.
Can an electromagnetic flowmeter be used? If possible, the 4-20mA signal from a flow meter can be used for interlocking; it’s not necessary to use switch-type instruments for this purpose.
If an electromagnetic flowmeter is used, there is a concern that the electrodes may get clogged by the medium.
It seems that for this case, only contactless methods can be used, such as external ultrasonic flow meters. The target flow meter mentioned upstairs is also good.
This post was last edited by ssln123 on 2017-10-25 at 16:11. Target-type ones can also get stuck due to adhesive substances; I’ve encountered such situations, and the only solution is to take them out and clean them regularly. External Doppler ultrasound devices are an option, but I’m not sure if there are any that are small enough; those I’ve seen were used for pipes with a diameter of over 80.
There’s no need to consider target-type flow switches; it is recommended to try viscosity-compensated flow switches available at https://www.ayt.hk. These are flow switches designed specifically for fluids with high viscosity. The product website is https://www.ayt.hk
A contactless microwave solid flow switch based on the Doppler principle should be able to solve your problem.
You might consider Keyence’s ultrasonic flowmeter, which is mounted outside the pipe and combines transmitter and receiver functions in one unit