During mill visits, I keep seeing this. The float valve controlling the feed into the Vacuum Dryer being restrained from complete shut position by rafia strings, chains and welding rods. According to the operator if not tied-up, like in photos, the float will remain stuck and no oil will enter the Vacuum Chamber. Do you face similar problem in your mill? Please share how you resolve this.
Spring selection is very important. Normal hardware shop can't get the spring, vehicle workshop easily can find.
We managed to solve this problem by using a spring to lift the Float Valve from its seat when it got stuck. Kekgian was right in that the buoyancy of the Float Valve is affected by the weight of the Float Valve. When the flow of oil into the Vacuum Dryer stops, the Float Valve closes to stop air from being suck into the Vacuum Dryer. When the flow of oil resumes, the Float Valve remains close and stuck to its seat. The Float Valve will float when submerged in the oil in the Feed Tank but it cannot overcome the suction pressure from within Vacuum Dryer. The spring attached to the Float Valve helps to counter the suction pressure from the Vacuum Dryer. When the Float Valve closes, the spring stretches and is under tension.
Thank you all for sharing. We will look into all your suggestions and share our experience.
May be can try to use less dense materials (aluminium) to fabricate the float valve, to give higher buoyancy force to the float.
From the second pictures I can assume that at one point one of the guide poles was briefly removed and reattached back to make way for the incoming feeding pipe and the repositioning might be off at the bottom part that causes the float to jammed when in closing position. Mybe can try to realigned back the guiding pole and have some clearance of about 2mm in between the float and the guides.
I am a retired engineer and can’t remember any of my mills facing this problem. However, I noted the temperature of right hand side feed is on the low side, any possibility of solidified oil causing momentary blockage. Another possibility is if there is any leakages on the float. Thanks.