Delay problem of pneumatic ball valve on metering tank
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The company’s metering tanks use weighing modules; once the specified weight is reached, the pneumatic ball valve at the feed inlet closes automatically. However, due to a 3–5 second delay in the closure of this valve, an excess amount of material is added. It was also considered to have the valve act earlier, but since the delay time varies each time, it is difficult to determine an optimal timing.
As a supplementary note, the workshop is a Class A explosion-proof workshop, so electric valves are not suitable for use there. This post was last edited by lxmem on 2008-11-1 14:27]
Why hasn’t anyone solved it? I’ve encountered the same problem as well. I hope some expert can give me some guidance!
1. It is possible to adjust the closing speed of the control valve by contacting it. 2. It is possible to moderately reduce the feeding speed toward the end of the feeding process during program design; for example, a control valve can be installed at the inlet, and as the feeding amount approaches the desired level, the opening degree of this control valve can be reduced until the appropriate amount is reached. Closing the valve should have little impact in this case.
(1) First of all, it should be noted that pneumatic ball valves are not particularly suitable for such operating conditions; control valves should be the preferred choice, as they can definitely solve this problem. (2) In the current situation, if replacement is not possible, I think the following approach could be tried: it is necessary to maintain a stable pressure in the air supply, so as to ensure a consistent timing for opening and closing the valve. The next step is to determine an appropriate time delay for closing the valve through testing, which should basically resolve the issue. Please refer to the above information.
Because the feeding speed and flow rate vary, pneumatic ball valves cannot avoid this problem. The control valve also cannot properly solve your problem.