We propose a microcapsule pump which is one of the realizable and useful micromachines today. We show that the microcapsule pump produces a microflow from the microstorage tank of solution, unlike other pumps, which pumps out the liquid from the inlet to the outlet of the flow. The proposed microcapsule pump has the function of the microflow from the storage tank, depending on the environmental condition. For example, this microactuator system can be applied to drug delivery requiring a long time, such as insulin injection for diabetic patients, and other medical applications. This microcapsule pump structurally consists of an inlet with a semipermeable membrane, an outlet with a one-way valve and a storage tank controlled by osmotic pressure. The outflow side has a one -way valve that prevents backward flow of the solution from the outlet to the inlet. Since this pump is applied to medical science, it is of a very simple structure and easy to handle. It is possible that the outflow volume of internal solution and the rate of osmosis can be changed using semipermeable membranes with different properties. The salient feature of this proposed actuator is that an external driving power supply is not required in this microsystem. The size of the prototype of this microcapsule pump is 5 mm in diameter and 9.8 mm in length. Its weight is 0.7 g.
