12/30/2023 0 Comments Harvest right freeze dry machine![]() ![]() ![]() When the Harvest Right freeze dryer “brain” sees that the dryer pressure remains below 600 mtorr with the heater on, it switches to the Final Dry phase. Final DryingĪfter hours of repeating this heater on/heater off drying process, the food will have so little moisture left that the vacuum pump is able to keep the vacuum chamber below 600 mtorr even with the heaters on. This means that one cycle takes about 25 minutes. With a large load of food, my dryer initially has the heaters on for about 4 and a half minutes and the heaters off for about 20 minutes. When the chamber pressure reaches 500 mtorr, the heaters come back on and the cycle repeats itself. The food cools off (because the heaters are off) and the vacuum pump starts reducing chamber pressure again. This causes pressure to continue to rise.ĭepending on the type and amount of food in the freeze dryer, the pressure will increase to 750 – 800 mtorr. However, the food is still warm and continues to give off more vapor. When the chamber pressure reaches 600 mtorr, the heaters are turned off. Then it begins to rise, as the vapor produced by the heating of the food overcomes the ability of the vacuum pump to maintain vacuum level. When the heaters are turned on at 500 mtorr, the vacuum pressure will continue to go down for awhile. It then traps that vapor on the chamber walls as ice. The freeze dryer removes moisture from the food by turning it into a vapor. The heaters cause the food to give off more vapor, which collects on the chamber walls as ice. Ice at these pressures does not melt, but goes directly to vapor. When the freeze dryer reaches 500 mtorr, it turns on heaters under the food trays. The dryer continues reducing the chamber pressure until it reaches 500 mtorr (0.01 psia). This time has been very consistent, within a few seconds difference for each load. It takes my dryer 4 minutes and 25 seconds to drop below 2500 mtorr. (For reference purposes 1 psi is equal to 51715 mtorr.) The dryer does not display the actual vacuum level until the dryer pressure has dropped below 2500 mtorr (0.05 psia). The front panel displays the pressure in the vacuum chamber in units of mtorr. When the freeze cycle is completed, the dryer turns on the vacuum pump. I have never changed this process time in any of the loads of food that I have run. Harvest Right says you can reduce this to 7 hours, if the food is already frozen when placed in the dryer. The factory default for this phase is 9 hours. (One day I plan to put a thermocouple in the dryer and check it, just for curiosity.) Freezingĭuring the freeze cycle, the freeze dryer refrigeration cycle cools the vacuum chamber and the food to -40☏ (also -40☌). The Harvest Right Freeze Dryer uses three different processing phases: freezing, drying and final drying. ![]() Review of Basic Harvest Right Freeze Dryer Operation Phases The cart makes it easy to move around, if needed, plus it provides storage. The dryer and the vacuum pump sit on a 25” x 37” plastic utility cart.I have done this from the very first load and Harvest Right now recommends doing this. I remove the water from the oil and filter the oil after each batch. When a load finishes, I drain the oil from the vacuum pump immediately. I place a JB Industries oil collection tank (Model DV-T1) under the pump stand.It also reduces stress on the vacuum hose from the dryer to the pump. This makes it easy to get to the pump drain valve, so I never have to move the pump. I built a small wooden stand for the vacuum pump to sit on.The meter allows me to monitor voltage, AC current draw, power (watts) and electrical energy used (kW-hrs). To figure out electricity costs for freeze drying a load of food, I hooked up a power meter.My dryer pulls over 16 amps at certain times during operation. Based on the data I've collected, I wouldn't recommend a standard household 15 amp circuit. There is a “non-GFCI” dedicated 20 amp electrical outlet.My wife would prefer in the garage, but I do woodworking there and it would get covered in sawdust. It is located in our laundry room because of the noise.As of this writing, I have processed 101 loads of food through the freeze dryer with the JB pump. I started with a JB Industries Eliminator Vacuum Pump, and have just switched to the new Harvest Right Pump. It is the middle sized unit as that was the only model offered at the time. I purchased my Harvest Right Freeze Dryer in November, 2016. Some Background on my Harvest Right Freeze Dryer and Home Freeze Drying Setup Using a Harvest Right Freeze Dryer Efficiently.Moisture Content of Foods for Freeze Drying.Harvest Right Freeze Dryer Electrity Cost per Load.Harvest Right Freeze Dryer Electrical Usage.Review of Basic Harvest Right Freeze Dryer Operation Phases.Some Background on my Harvest Right Freeze Dryer and Home Freeze Drying Setup. ![]()
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