So I'm knew to freeze drying! But I'm an HVAC tech that runs a vacuum pump for a living, removing moisture is critical in a HVAC system! What we have come to know from years of running a vacuum pump is that pumps that are higher cfm in small spaces are not better at removing moisture! they move so much air that they actually create ice! The ice is still moisture and shows up on a enthalpy meter, which measures moisture in air. High cfm pumps work well when there are larger areas. This is my experience in HVAC systems. Most techs run 6-8cfm pumps on small to med size systems 10-16cfm pumps on large systems with hundreds of feet of copper piping. Hope this information helps.
is there a vacuum gauge on the freeze dryer? If either pump can hold the same level of vacuum then you wouldn't expect a difference. If a lower CFM pump can pull a hard vacuum then a higher CFM pump won't move more water molecules, but it will draw the pressure of the chamber down to its limit faster, possibly by a few minutes, which won't make much difference on a 25 hour + cycle . It's possible the cheaper pump actually pulls a harder vacuum. At very low vacuum pressures larger hoses and fittings and shorter hoses might help (think about gas molecules trying to randomly bounce their way out of the closed system) and i would think adding heat to the system as radiant energy would help increase the vapor pressure of the water molecules that still need to boil off... adding heat would tend to raise the pressures in the chamber. There may be a tradeoff between food quality and drying times if higher temperatures are needed to go faster. I haven't done any freeze drying myself yet, but I worked with some vacuum tech in an unrelated field.
I can recall the *INCREDIBLE* argument between my mother and father back in the late 1960s, when my father, a pioneering refrigeration mechanic, unilaterally purchased an expensive, small, portable vacuum pump that would significantly increase his ability to work more efficiently and more quickly. Both for the employer whom he worked for, as well as for himself for those on-the-side independent jobs. Those of you who lament at the cost of freeze-dryers and all of the ancillary components, well, *NOTHING* to do with either high-quality vacuum pumps or high-quality freeze dryers has *EVER* been inexpensive.
Commercial FD use same type of vacuum pumps only greater CFM. These are driven by multi phase electric power motors which is capable of reaching 0.3 mtorr. Evaporative cooling was possible by refrigeration was much greater depth of cooling We could flash freeze products if required. You don’t need that for food stuffs. Speciality FD would have the fluids boil and foam up before dropping the temperature flash freezing. Vacuum is to get sublimation. Exercise look up tri state point for water We used water filled vials to test and validate the FD. Nice experiment.
You have to start with vacuum is vacuum. Then you have to assume that the premier vacuum pump works otherwise why would harvest right use it. So if harvest right can pull a vacuum to X and hold it and a bigger pump can pull a vacuum to X and hold it there there is no difference to that part of the cycle. The difference in times might come in play with bigger chambers. The smallest freeze dryer might take x amount of time to reach the desired vacuum whereas the largest freeze dryer, having more volume, might take 4X the time to reach the same vacuum. The larger pump could reach the desired vacuum faster than the premier pump but it is not going to be 4X faster. So the only real difference between the two pumps is how fast the larger pump can pull a vacuum compared to the smaller pump. Not much difference at all. The difference it cycle times could be the fact that the larger pump went second and there was hidden moisture still in the system. The other difference could be that you ended up with the "same" oat milk but with different batch numbers where one batch had less or more water in it and what you did is prove that the company was trying to stretch the volume by adding more water to one batch over the other or that there were two production lines with slightly different calibrations that produced the "same" oat milk. The practicable difference between the two pumps is the cost and that one of them is designed to operate longer and cleaner than the other. In this case you get what you pay for . If you need a pump that will still be doing the same thing in three years from now with continuous use or do you need a pump that might still be working three years from now with a lot less use. If you can purchase 2-3 premier pumps for the same price as the larger pump most people would be better off with the premier pump. The other thing to consider is that there are other vacuum pumps out there that are cheaper than the large pump and might have a longer life than the premier and be rebuild able. Thanks for the test.
Well, its an interesting test, its also interesting your comment about running multiple dryers with one pump. Perhaps the middle of the road answer to buying a $5000 larger pump would be to run 2 premier pumps in parallel for faster evacuation times or possibly in series for lower total vacuume ?
A very interesting experiment. I may have missed this, but at what micron level is the unit operating? Also, is the Leybold new? Just an observation, but I would think one of the limiting factors for speed of performance would the the condenser. I would be interested to see the experiment mentioned with multiple units using the one vacuum pump.
My older freeze dryer has been taking forever to dry. I can put identical things in it and my newer maching and the older one will take almost 3 times as long. I thought it was the referbished pump I had just purchased, but when I put the older pump back on it still took much longer. Both pumps are oil free. I wonder if the machine would do better with a soft ware update? I was sure it was the pump unti I put the old pump back on and it took just as long. I . It seemed to be taking longer before getting the newer referbished pump, but since I wasn't doing the same kind of things I didn't really pay attention untill something I did took 3 days and has never gone that long before.
Depending on how old the FD is, a software update could make a dramatic change. I would call HR and get their take on it before doing the update though.
Just got a GS53 Avid Armor, what settings do you recommend for mylar bags. I'm having problems with the bags blowing off the heat strip. I've got it set at PCP02 with 3.5 time for the sealer.
So I'm knew to freeze drying! But I'm an HVAC tech that runs a vacuum pump for a living, removing moisture is critical in a HVAC system! What we have come to know from years of running a vacuum pump is that pumps that are higher cfm in small spaces are not better at removing moisture! they move so much air that they actually create ice! The ice is still moisture and shows up on a enthalpy meter, which measures moisture in air. High cfm pumps work well when there are larger areas. This is my experience in HVAC systems. Most techs run 6-8cfm pumps on small to med size systems 10-16cfm pumps on large systems with hundreds of feet of copper piping. Hope this information helps.
That is great information. Thanks for sharing that with us
is there a vacuum gauge on the freeze dryer? If either pump can hold the same level of vacuum then you wouldn't expect a difference. If a lower CFM pump can pull a hard vacuum then a higher CFM pump won't move more water molecules, but it will draw the pressure of the chamber down to its limit faster, possibly by a few minutes, which won't make much difference on a 25 hour + cycle . It's possible the cheaper pump actually pulls a harder vacuum. At very low vacuum pressures larger hoses and fittings and shorter hoses might help (think about gas molecules trying to randomly bounce their way out of the closed system) and i would think adding heat to the system as radiant energy would help increase the vapor pressure of the water molecules that still need to boil off... adding heat would tend to raise the pressures in the chamber. There may be a tradeoff between food quality and drying times if higher temperatures are needed to go faster. I haven't done any freeze drying myself yet, but I worked with some vacuum tech in an unrelated field.
Yes the screen tells you the vacuum indication.
Great test, I also think your divider , more drying surface are comment was spot on.
You did a great job of controlling the variables. That is very impressive
Looking forward to the follow up video and the trouble shooting results!!
Does it show in the logs when the pump starts and how long it runs? Maybe you can compare with that to see if there's a difference.
I can recall the *INCREDIBLE* argument between my mother and father back in the late 1960s, when my father, a pioneering refrigeration mechanic, unilaterally purchased an expensive, small, portable vacuum pump that would significantly increase his ability to work more efficiently and more quickly. Both for the employer whom he worked for, as well as for himself for those on-the-side independent jobs.
Those of you who lament at the cost of freeze-dryers and all of the ancillary components, well, *NOTHING* to do with either high-quality vacuum pumps or high-quality freeze dryers has *EVER* been inexpensive.
Commercial FD use same type of vacuum pumps only greater CFM. These are driven by multi phase electric power motors which is capable of reaching 0.3 mtorr. Evaporative cooling was possible by refrigeration was much greater depth of cooling We could flash freeze products if required. You don’t need that for food stuffs. Speciality FD would have the fluids boil and foam up before dropping the temperature flash freezing. Vacuum is to get sublimation. Exercise look up tri state point for water We used water filled vials to test and validate the FD. Nice experiment.
You have to start with vacuum is vacuum. Then you have to assume that the premier vacuum pump works otherwise why would harvest right use it. So if harvest right can pull a vacuum to X and hold it and a bigger pump can pull a vacuum to X and hold it there there is no difference to that part of the cycle. The difference in times might come in play with bigger chambers. The smallest freeze dryer might take x amount of time to reach the desired vacuum whereas the largest freeze dryer, having more volume, might take 4X the time to reach the same vacuum. The larger pump could reach the desired vacuum faster than the premier pump but it is not going to be 4X faster. So the only real difference between the two pumps is how fast the larger pump can pull a vacuum compared to the smaller pump. Not much difference at all. The difference it cycle times could be the fact that the larger pump went second and there was hidden moisture still in the system. The other difference could be that you ended up with the "same" oat milk but with different batch numbers where one batch had less or more water in it and what you did is prove that the company was trying to stretch the volume by adding more water to one batch over the other or that there were two production lines with slightly different calibrations that produced the "same" oat milk.
The practicable difference between the two pumps is the cost and that one of them is designed to operate longer and cleaner than the other. In this case you get what you pay for . If you need a pump that will still be doing the same thing in three years from now with continuous use or do you need a pump that might still be working three years from now with a lot less use. If you can purchase 2-3 premier pumps for the same price as the larger pump most people would be better off with the premier pump. The other thing to consider is that there are other vacuum pumps out there that are cheaper than the large pump and might have a longer life than the premier and be rebuild able.
Thanks for the test.
The FD is tuned to certain parameter, perhaps it needs to be reprogrammed to use the more abundant power in a stronger vacuum pump
Well, its an interesting test, its also interesting your comment about running multiple dryers with one pump. Perhaps the middle of the road answer to buying a $5000 larger pump would be to run 2 premier pumps in parallel for faster evacuation times or possibly in series for lower total vacuume ?
A very interesting experiment. I may have missed this, but at what micron level is the unit operating? Also, is the Leybold new? Just an observation, but I would think one of the limiting factors for speed of performance would the the condenser. I would be interested to see the experiment mentioned with multiple units using the one vacuum pump.
My older freeze dryer has been taking forever to dry. I can put identical things in it and my newer maching and the older one will take almost 3 times as long. I thought it was the referbished pump I had just purchased, but when I put the older pump back on it still took much longer. Both pumps are oil free. I wonder if the machine would do better with a soft ware update? I was sure it was the pump unti I put the old pump back on and it took just as long. I . It seemed to be taking longer before getting the newer referbished pump, but since I wasn't doing the same kind of things I didn't really pay attention untill something I did took 3 days and has never gone that long before.
Depending on how old the FD is, a software update could make a dramatic change. I would call HR and get their take on it before doing the update though.
The premier pump is the best. No need to use anything different. Had ours for years and it is a workhorse.
Just got a GS53 Avid Armor, what settings do you recommend for mylar bags. I'm having problems with the bags blowing off the heat strip. I've got it set at PCP02 with 3.5 time for the sealer.
love that pump would love to have one
Did you figure out the issue?
shocker!
I never use paper or silicone with liquids. Good experiment though.
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Additional time and a lot more cost, I think it's pretty clear. Not worth paying the extra money!
If it costs more than the dryer, I can't afford it.
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Well that sucks! I hope you find other benifit to your new pump!