1. System for the delivery of intravenous fluid containing a disposable part in contact with intravenous fluid during delivery of intravenous fluid； and a reusable portion isolated from contact with intravenous fluid during intravenous fluid delivery； wherein the disposable portion comprises a liquid chamber having an opening； and a pump membrane forming the side of the liquid chamber； and the reusable part comprises a piston arranged to move in and out opposite the pump membrane, the piston being in the housing and the pump membrane being flexible； a sealing membrane attached to the piston, wherein the sealing membrane is flexible； and a vacuum chamber defined by the region between the pump membrane, the sealing membrane, the piston and the housing, while the vacuum chamber is configured to maintain vacuum during intravenous fluid delivery, and the sealing membrane is configured to move with the piston and maintain the vacuum in the vacuum chamber during movement piston. 2. The system of claim 1, wherein the vacuum chamber has a sealable opening. The system of claim 1, further comprising a vacuum source for removing air from the vacuum chamber. The system according to claim 1, in which the disposable part is configured to be attached to the reusable part with a sealed connection. The system according to claim 1, additionally containing a tool in the form of a screw thread with a nut on the disposable part and the reusable part, while this tool forms a tight connection. The system of claim 1, further comprising an introductory t1. Система для доставки внутривенной жидкости, содержащая одноразовую часть, контактирующую с внутривенной жидкостью во время доставки внутривенной жидкости； и многоразовую часть, изолированную от контакта с внутривенной жидкостью во время доставки внутривенной жидкости； при этом одноразовая часть содержит жидкостную камеру, имеющую отверстие； и насосную мембрану, образующую сторону жидкостной камеры； а многоразовая часть содержит поршень, вы
