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Post by turbokinetic on Sept 8, 2023 12:55:47 GMT
In this video I replace a broken sensing tube on this 94 years old control. These are often broken when they are straightened and re-bent during control removal and installation. Used smaller tubing for the connection from the control to the sensing bulb, to allow for better flexibility and less chance of damage. Original charge in the bellows was sulphur dioxide. A much safer and more easily obtained working fluid isobutane (R600A). The temperature / pressure relationship is similar but not the same as SO2, therefore adjustments of the control will be required. The control is charged with a vapor only charge. Should not have liquid in the stem or bellows. Pressure only needs to exceed the saturation pressure for the highest expected control operating point.
Sincerely,
David
https://youtu.be/5P5YV2Luj8w
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Post by ckfan on Sept 8, 2023 14:30:04 GMT
Saving a tall control. Great work!
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Post by turbokinetic on Sept 8, 2023 15:29:08 GMT
Saving a tall control. Great work! Thank you so much Ray! |
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marko
7 Cubic Foot
Posts: 159
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Post by marko on Sept 8, 2023 23:10:14 GMT
This is amazing. I did this procedure on another control following David's method, using butane lighter fuel. While it did work, I found that getting the equilibrium of charge correct to be somewhat challenging due to the fact that regardless of the ambient temperature that the process was performed at, some amount of liquid inadvertently made it into the system. Of course, this should not matter much, as some liquid is required for a consistent vapor pressure.
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marko
7 Cubic Foot
Posts: 159
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Post by marko on Sept 8, 2023 23:17:27 GMT
Perhaps the Volkswagen air cooled engine thermostat could be used as a silphon.
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Post by turbokinetic on Sept 9, 2023 1:16:41 GMT
This is amazing. I did this procedure on another control following David's method, using butane lighter fuel. While it did work, I found that getting the equilibrium of charge correct to be somewhat challenging due to the fact that regardless of the ambient temperature that the process was performed at, some amount of liquid inadvertently made it into the system. Of course, this should not matter much, as some liquid is required for a consistent vapor pressure. Perhaps the Volkswagen air cooled engine thermostat could be used as a silphon. Thanks! I didn't mention but it is very important when using butane refills, to ensure they are not charged with nitrogen on top of the butane. Some of them are pressurized this way to facilitate charging lighters with liquid. The Ronson ones seem to be the highest ratio of isobutane to norbutane and therefore are the best R600A. However, I always tap off liquid from the can and allow it to vaporize in the gauge hoses to ensure that NCG is not charged. I feel bad that I didn't mention this in the video. Interesting about the VW thermostat, but those are vintage engines and I would hate to cannibalize their parts. Sincerely, David |
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Post by 508gm1 on Sept 9, 2023 19:43:46 GMT
I came across this company but assume you have as well already : fultonbellows.com/bellows-assemblies/I will inquire with the pressure instrumentation shop we use at work on Monday & see if they have a source. |
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Post by turbokinetic on Sept 9, 2023 19:58:36 GMT
I came across this company but assume you have as well already : fultonbellows.com/bellows-assemblies/I will inquire with the pressure instrumentation shop we use at work on Monday & see if they have a source. Wow, thanks. I had not seen that. Interestingly, that company is the descendent of Fulton Sylphon who produced many of the thermostat bellows I have seen in the antiques. |
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Post by 508gm1 on Sept 19, 2023 8:51:11 GMT
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Post by turbokinetic on Sept 19, 2023 12:18:43 GMT
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Post by aricsworkshop on Mar 7, 2024 0:11:51 GMT
In this video I replace a broken sensing tube on this 94 years old control. These are often broken when they are straightened and re-bent during control removal and installation. Used smaller tubing for the connection from the control to the sensing bulb, to allow for better flexibility and less chance of damage. Original charge in the bellows was sulphur dioxide. A much safer and more easily obtained working fluid isobutane (R600A). The temperature / pressure relationship is similar but not the same as SO2, therefore adjustments of the control will be required. The control is charged with a vapor only charge. Should not have liquid in the stem or bellows. Pressure only needs to exceed the saturation pressure for the highest expected control operating point. Sincerely, David
I came here in hopes of finding information regarding where to source/how to fix a broken sensing tube, and and very pleased that it took under 10 minutes to find this. THANKS SO MUCH! |
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Post by turbokinetic on Mar 7, 2024 1:40:54 GMT
In this video I replace a broken sensing tube on this 94 years old control. These are often broken when they are straightened and re-bent during control removal and installation. Used smaller tubing for the connection from the control to the sensing bulb, to allow for better flexibility and less chance of damage. Original charge in the bellows was sulphur dioxide. A much safer and more easily obtained working fluid isobutane (R600A). The temperature / pressure relationship is similar but not the same as SO2, therefore adjustments of the control will be required. The control is charged with a vapor only charge. Should not have liquid in the stem or bellows. Pressure only needs to exceed the saturation pressure for the highest expected control operating point. Sincerely, David
I came here in hopes of finding information regarding where to source/how to fix a broken sensing tube, and and very pleased that it took under 10 minutes to find this. THANKS SO MUCH! So glad to help! Glad you found it. I have made more videos on this, as well. |
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