Abstract: Apparatus for weighing out powder and liquid and mixing the powder in the liquid comprising two receptacles (2 and 3, respectively) and a pump (8), which are connected to each other in a unit (1) which is suspended in a weighing machine (4). A desired quantity of liquid, which is determined by the weighing machine (4), is supplied to one (2) of the receptacles and a desired quantity of powder, which also is determined by the weighing machine (4), is supplied to the other receptacle (3). After that, the liquid is caused to circulate through the pump and the powder is let into the suction conduit (7) of the pump (8) and is thereby mixed in the liquid. The unit also includes a heat exchanger (14) which is connected to the pressure side of the pump (8) for thermal treatment of the liquid.