Abstract: Method and apparatus for transfer of material such as liquids or fluid like solids into a high-pressure fluid stream to establish a desired flow rate by using a metering device, a reservoir for mixing fluids and solids, a first conduit connected to a top of the reservoir for flowing fluids and controlling atmosphere pressure, a second conduit connected to a top of the reservoir for supplying solids, the metering device connected to the bottom of the reservoir and controlled by a metering controller for controlling pressure of a mixture of fluids and solids, and a cross conduit mounted to the metering device for injecting the mixture of fluids and solids into the fluid stream.