NOVELTY - The device (1) has guide plates (6) by which one partial flow is supplied to the main portion (11) of mixing apparatus and is mixed with the liquid. The other partial flow is supplied to other portions of the mixing apparatus and is mixed with the gas to form an aerosol. The liquid from an electromagnetically driven reciprocating piston pump (2) is metered and conveyed. The main portion of mixing apparatus and the outlet (10) of reciprocating pump form a structural unit so that groups of guide plates are coaxially arranged with piston pump.    USE - Device for metering and mixing fluid streams, used in burner, fuel cell, reformer and facility for after-treatment of exhaust gas of combustion engine.    ADVANTAGE - The use restriction is largely avoided while decreasing the production cost. The working frequency of piston pump is defined by electrical drive, and the quantity metered at a single stroke of the reciprocating pump of the operating frequency in the normal workspace is very slightly affected. The oxidation-explosive mixture of the gas and liquid is formed for wide ranges of temperature and pressure after the complete mixing of two fluids in all portions of mixing device. The second group of the guide plates conducts the current of liquid by arrangement and molding in such a way that sturdy flame is produced. Since no additional devices such as feed pump or compressor/blower or metering device are required, the manufacturing cost can be reduced. The two-fluid nozzle is good so that fine mixture preparation can be better obtained than with single-fluid nozzle, and finer droplet distribution by pressure increase can be achieved in a downstream mixing effect. Since fewer components are required, the installation space and weight of the device can be reduced, and shorter mixing feasible routes are realizable.    DESCRIPTION OF DRAWING(S) - The drawings show the schematic views of the metering and mixing device, and the piston pump.    Device for metering and mixing fluid streams (1)    Reciprocating pump (2)    Guide plate (6)    Outlet of reciprocating pump (10)    Main portion of reciprocating pump (11)