Homemade vacuum pump oil filter
It is once again time to change the filter material in our homemade vacuum pump oil filter for our Harvest Right home freeze dryer. The oil filtering system is a simple one comprised of a Brita water filter. Their filter is removed from the pitcher and a new one is made by rolling up a large potion of a roll of toilet paper. That plug of toilet paper is made to be a little large in diameter than the hole where the Brita filter is intended to go.
Remove the old filter material
The old toilet paper filter will need to be removed and the pitcher cleaned. The old filter is going to be full of oil and food particles from the food that has been run through the freeze dryer. Gloves such as nitrile or Food handlers glove for handling the the old filter and cleaning up the pitcher are a good idea. You can grab the filter from the top and pull it out of the pitcher, or remove the part that holds the filter so you can push it out from the bottom.
A finger will work for most people to push the filter out from the bottom. For those with large diameter fingers an improvised tool such a pencil or screw driver will push the old used toilet paper filter from the pitcher housing. Having a rag or paper towel on hand to wipe the oil from your tool would be a good idea.
Clean out the Brita pitcher
After the old toilet paper filter is removed there will be a lot of gunk that is comprised of food particles that needs to be cleaned. We use paper towels for this task. Here is what the inside of our homemade filter looks like before cleaning.
To prevent the mess from getting into the pitcher one should consider cleaning the mess out as much as possible before removing the filter material. After we have wiped out the mess it is simple to push the toilet paper filter out from the bottom. Here is what our filter looks like at the time we replaced it. It is gross, but you can see all the food particles that this removes from the oil.
Replace the filter material
Once the pitcher clean and the old toilet paper filter material is removed it is time to add the new filter. To replace the dirty filter material you see above just take a roll of your toilet paper and start rolling it.
You will want to make the diameter of the filter slightly larger than the hole in the pitcher. When the toilet paper filter is pushed into the pitcher it should fit snugly but not require a lot of force to get into place. If the filter fits loosely the oil will flow past it and not get filtered. If it is too tight the oil may not pass through the roll.
Here is our homemade vacuum pump oil filter cleaned, a new toilet paper filter is in place.
Which Brita pitcher to use
I prefer the larger pitcher that can handle a couple quarts of oil at a time. We bought the 10 cup Brita filter and are very happy with it. These are often available used at 2nd hand stores for a few dollars. You can expect to spend 20 to 30 dollars if you buy one new