In the patent literature, what do you mean by the weight of ingredients, that is, 80 parts of water and 20 parts of citric acid, that is, 80 grams of water.

It should be understood this way. If100g solution is needed, including 80g water and 20g citric acid, the ratio of water to citric acid is 8:2. If you want to mix 1000 ml solution, then use 800 ml water and 200 ml citric acid. And so on.